Debris removal tools operate on several principles. Some are run in the hole and simply pulled out and capture what falls into a basket on the way out. Other designs involve a peripheral seal and tool movement with the seal extended to route fluid flow through the tool when it is moved downhole so that a screen can block the debris and retain it in the tool body while the fluid continues through. Some tools use circulation or reverse circulation through a string running from the surface that supports the tool. In some of these designs the flow with debris is urged into the debris catcher while the main fluid stream without the debris continues to the surface.
Another type of debris removal tool uses an eductor to draw fluid into the tool that is part of a bottom hole assembly. The eductor exhaust goes into the annular space and recirculates to the surface. Normally about 3 times the volume circulates from the eductor exhaust of the tool to the surface than the volume induced to flow into the tool by the negative pressure created by the eductor. One such tool is the VACS tool in Product Family H 13125 sold by Baker Oil Tools. FIG. 1 is a schematic of this tool. It has an inlet 10 at a lower end that leads to an inlet tube 12. A deflector cap 14 keeps debris from falling back into tube 12 if circulation represented by arrow 16 is stopped. Flow exits from under cap 14 as indicated by arrow 18 and then flows through screen 20 as indicated by arrow 22. Debris falls outside the screen 20 and into annular space 24 where it is collected to be removed when the tool is brought to the surface. Arrow 26 is the debris free fluid being sucked into the inlet 28 of the eductor or venturi device 30. Motive fluid for the venturi 30 is provided by pumped fluid down the tubing string 32 as indicated by arrow 34. It enters the motive fluid inlet 36 and creates a reduced pressure zone at inlet 28. The two streams commingle and exit out the eductor outlet 38 and then out through some aligned housing ports 40 as indicated by arrow 42. Most of the flow goes uphole as indicated by arrow 44 and the rest goes downhole to the tool bottom as indicated by arrows 46 and then 16 due to the negative pressure created by the eductor 30 at its inlet 28.
FIG. 3 shows the debris removal tool T supported by a tubular string 100. A bushing 102 is fixedly supported at shoulder 104 and has a peripheral seal 106. Inside of passage 108 is a sleeve 110 with an exterior seal 112 against the passage 108. Passage 114 leads to an eductor 116 whose outlet port 118 is aligned with housing exit port 120. Sleeve 122 is pinned at pin or pins 124 so that it covers the housing port 120. Split ring 126 has built in radially outward bias, and in the FIG. 3 position is illustrated in a radially compressed state. Eventually it will be brought into alignment with groove 128 to lock the position of sleeve 122 in the FIG. 4 position. A support ring 130 has a plurality of holes 132 along with a shoulder 134 in the central opening to accept sleeve 110 at a shoulder 136 that surrounds it. A ball 140 can be pumped down to land on the top of sleeve 110 to block the passage 142. With pressure applied to the ball 140, the shear pins 124 break and the sleeve 110 takes with it sleeve 122 to open the passages 102 to all the eductors 116 that are assembled in the device. Ports 120 are now open and flow can go in an uphole direction as shown by arrow 143 or in a downhole direction as shown by arrow 144. The flow in the downhole direction 144 is induced by the reduced pressure created by the eductors 116 in the passage around sleeve 110 as illustrated by arrow 146.
FIG. 2 shows the eductor 30 in more detail and illustrates the problem solved by the present invention. During run in, ball 48 is not in the position shown in FIG. 2 landed on seat 50 in sleeve 51 that does not move. Flow 34 coming down the string 32 can go two ways. It can go into the eductor inlet 36 which is always exposed and flow uphole as indicated by arrow 44 or without ball 48 in position on seat 50 it can flow down passage 54 to the bottom of the tool and exit at the lower end 10 and then come up the surrounding annular space and join with the flow from the eductor exiting from the opening 40.
The problem in the past is that during running into a well with debris to be removed it is helpful for advancing the tool that as much circulation fluid be directed at the bottom outet of the tool 10 as is possible for fluidizing the debris and preventing the tool from getting stuck. As presently configured not all the flow that is pumped down the string 32 gets down to the outlet 10 at the bottom of the tool. Some of the pumped fluid down the string 32 goes through the eductor 30 and turns uphole after exiting outlets 40 and does nothing for the need to fluidize debris ahead of the tool being run downhole. It would be advantageous to be able to direct all the fluid being pumped through the string 32 when advancing the tool out through its lower end 10 and the present invention allows for doing just that and still allowing the tool to work in the way that it normally operates.
The tool of the present invention allows all the flow heading down the string 32 to get out to the bottom 10 of the tool by keeping the housing outlet 40 closed for run in. After the lower position is reached where debris removal is set to start a ball is dropped to shift a sleeve to open the outlet 40 to allow the tool to operate in the manner described above. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description and the associated drawings while recognizing that the full scope of the invention is to be determined from the literal and equivalent scope of the claims.